Boiler Leaking Water – What Should I Do?

Let’s state the obvious here – a leaking boiler is not a good sign! Despite being a relatively common issue, it is one that requires the urgent help of a gas safe registered engineer.

Although there may be some things you can do to keep the damage at bay while you wait for a qualified engineer, fixing a leaking boiler is not a DIY situation.

A boiler leaking water or gas requires immediate attention and when left for too long, can lead to other problems that are harder to handle, such as rust and damaging electrical functions inside your boiler.

Here’s what you do need to do as soon as you notice your boiler leaking and everything you need to know when it comes to your leaking boiler.

What should I do if my boiler is leaking?

Boiler leaking water

If your boiler is leaking water you should locate all the leaks and use a bucket or container to stop the leak from damaging your floor and wipe up the water that had already spilled. It may also be worth tightening the fitting to see if that stops or slows the leak.

The next steps are to turn off the water supply and switch off the heating. Finally, it is important to contact a gas safe registered engineer to take care of the problem.

Can I fix a leaking boiler myself?

It’s a good idea to call in a qualified engineer to fix a leaking boiler in order to make sure it is properly repaired, as this issue can lead to more serious damage that is harder to fix.

If you are having some trouble getting a heating engineer over to you immediately then there are some short term solutions to minimise the issue. However, do bear in mind that a DIY attempt should only be made on very small leaks.

In this instance, you could use a boiler leak sealant or sealer which is an additive that forms a boiler leak seal to stop or block the leakage. This is a temporary solution as all it does is stops the leak from causing further damage to your home. It is important to consult an engineer even if you have successfully managed to keep the leak at bay, as it is necessary to find the root cause of the problem and resolve it.

What type of boiler leak do I have?

Your boiler could be leaking gas, water or oil. Here are some telltale signs to help you figure out what is going on with your boiler and what you will need to do!

Gas Leak

A gas leak is not particularly common as modern boilers, such as condensing boilers, have a sealed combustion chamber where they burn gas or oil and the fumes are released outside for your safety, preventing harmful gasses from getting into your home. However, things don’t always work as well as they are meant to, so it is important to keep an eye out for telltale signs of a gas leak.

Signs that your boiler is leaking gas include black stains above or near the boiler, an unusual amount of condensation on your windows, and the flame that confirms your boiler is working, known as a pilot light, turning orange or yellow instead of being blue.

Additionally, in most cases, you will be able to smell the gas leak unless your boiler is leaking carbon monoxide as it can often be odourless. This is very dangerous, which is why it is a good idea to have a carbon monoxide detector installed in your home.

If your boiler is leaking gas, you may be feeling dizzy, sick, tired or have headaches. If you are concerned that your boiler is leaking gas, it is important to act fast – you will need to open all your windows and doors, do not light any naked flames, including cigarettes and call the Gas Emergency Services for free.

Depending on how you feel, it may also be worth getting some medical advice just to ensure your safety and well-being.

Oil Leak

Similar to a gas leak, sealed combustion chambers should usually prevent this type of leak from happening in modern boilers.

Obvious signs of a boiler leaking oil are spot oil stains or pooling in addition to a stronger oil smell than usual.

If you are concerned that your boiler is leaking oil you need to locate the oil tank and close the tap or valve and then open the windows. Opening the windows is an important step as it prevents harmful fumes from building up.

When it comes to clearing and collecting the leaking oil, try to collect it and contain it in a tub or put putting down sand or earth. It is essential that you make sure it is safe first before doing so, and avoid washing the oil away.

Call a heating engineer as soon as possible to come and repair the oil leak, and be mindful of whether you or anyone else in your home is feeling sick or dizzy as you will need to leave the house instantly.

Water Leak

Although it is important to call a gas safe engineer as soon as possible to prevent further damage to your boiler, if your boiler is leaking water, it does not require urgent action in terms of your own personal safety as with oil and gas leaks.

However, it is important to turn the electricity off to avoid the risk of an electric short-circuit and to prevent any damage to your central heating system.

An obvious sign of your boiler leaking water would be a water spillage. This may not always be the case as another sign is if your boiler stops working or cuts out because of low pressure, and then losing pressure quickly even if you top it up. Additionally, if you can see stains, mould or dampness on the walls, ceilings or woodwork then this is another clear sign of water leaking from your boiler.

Of the three types, water leaks are the most common across all varieties of boilers and there is usually a root cause that leads to a boiler leaking water. This is why it is important to get in touch with a gas safe engineer to take a look and resolve the problem properly, rather than relying on short term fixes, such as a boiler leak sealant.

Let’s take a look at what may be causing your boiler to leak water.

Why is my boiler leaking water?

Boiler leaking water

There are several reasons why your boiler may be leaking water, such as corrosion and incorrect or faulty installations. It is important to call in a heating engineer to find the root cause and resolve the matter quickly to avoid further, long-lasting damage.

Here are some reasons why your boiler may be leaking water.

  1. Pressure. Pressure can push everyone to their boiling point, and your home boiler is no different! When your boiler’s pressure is too cry, the pressure release valve (PRV) will either let out the water causing a leak or some parts. internally may fail which in turn leads to a leak. Most boilers have a pressure gauge which should be around 1 bar and green, especially if you have a Combi Boiler. If the pressure gauge is above the green bar, then your boiler is under pressure! Often, bleeding your radiator can help relieve the pressure in your boiler.
  2. Corrosion. It is not unusual for pipes and hot water cylinders to corrode, become brittle and then deteriorate, eventually causing a leak. This is why regular servicing is so important – if one single part is corroded, it is relatively cheap to call in a Gas Safe Engineer to replace it. However, if the corrosion is quite severe then it may be necessary to purchase a new boiler altogether. The more leaks you have can also be an indicator of how corroded your boiler is.
  3. Faulty Installation. If you have water leaking from the pipes immediately under the boiler, the most likely cause is that some joints in the pipework have not been fitted correctly. Pipe fittings are the most likely cause especially if you have just installed a new boiler. Nevertheless, this is no cause for panic and outrage, it is quite common for new boiler installation to have small leaks. All you need to do is contact your boiler installer to fix the leaks and correct the pipework.
  4. Broken seals. Not to state the obvious here, once a seal breaks or becomes damaged, it does lead to water escaping which results in a leaking boiler. Seals are fitted around or on parts and joints within your boiler and if your boiler becomes corroded over time, it can cause the seals to become damaged too. Once this happens, the water that is pumped through the system then leaks through the seal and often at an alarmingly rapid rate. So, if you have boiler leakage with quite a bit of water and if it is leaking quickly, then impaired seals may be the culprit. Although applying a bit of sealant may be a good short term solution to stop the flow of water leaking, you will need a Gas Safe Engineer to take a look and may need to replace your boiler.
  5. Faulty heat exchanger. If your boiler is particularly old or of low quality, then it is not uncommon for the heat exchanger to stop working or crack. Unfortunately, the heat exchanger is the most expensive part to replace and to add to the wave of bad news, it is not easy to identify whether your heat exchanger is leaking yourself. You will need to call in a Gas Safe Engineer to take a look at the problem and investigate whether your heat exchanger is the problem. In most cases, a failed heat exchanger is an indicator that it may be time to invest in a new boiler.
  6. Temperature. This leak is definitely one to watch out for, as it could lead to scaling water coming out from your taps. Boilers usually include a temperature control valve (TCV) and this keeps an eye on the temperature of the water inside your boiler and prevents the water temperature from getting too high. However, if the TVC is unable to regulate the temperature, it may lead to leaks coming from the temperature valve. This is the result of a fault with the temperature sensors and again, requires a professional investigation by a Gas Safe Engineer.

How dangerous is a leaking boiler?

Leaking boiler

Unlike a gas leak, a leaking boiler does not pose a threat to your wellbeing and therefore in that sense, may not be considered dangerous.

However, a leaking boiler can be a huge danger to your bank account! When left unattended, or if you try to use a temporary solution permanently, such as using a sealant then this could lead to bigger and more expensive problems.

Not only can a leaking boiler cause damage to your boiler, such as rusting but it can also impact your entire home too. It is best to not use your boiler while is it leaking and until you have repaired or replaced it, as the leaks could end up spilling onto other electrical parts and short-circuiting. The leaks could also spread around your house, damaging your furniture, floors and other belongings racking up a bill to repair your boiler and the damage done to your home.

Additionally, unless it is a new boiler being installed incorrectly, a leaking boiler is usually a dramatic way for your boiler to say goodbye. Although the issue can be solved, in most cases leaking boilers are an indicator that it may be time to look for a replacement.

However, this does give you the opportunity to review the needs of your home and see if you can invest in more affordable boilers that suit your home’s needs better.

How do I stop my boiler from leaking?

As the saying goes, the best offence is a good defence.

There are some measures you can take to ensure the longevity and good health of your boiler to prevent your boiler from leaking and boiling over!

Here are some actions you can take to check up on your boiler.

  1. Annual Servicing. Getting your boiler serviced regularly allows professionals to catch minor problems before they become major ones and stops issues from developing further, such as corrosion of components within your boiler. Additionally, it is a warranty requirement and your warranty will be invalid without regular or yearly servicing.
  2. Chemical Flushes. As mentioned, the heating system is the most expensive part to fix when something goes wrong there, so it is worth investing in the system or chemical flushes to cleanse your heating system and prevent the build-up of anything that would inhibit it from working properly.
  3. Magnetic Boiler Filter. These are magnets that work to collect any metallic debris from your heating system and it is important to make sure any new boilers are fitted with them. Magnetic boiler filters help extend the life of your boiler by preventing blockages from the build-up of debris in your heating system as well as lowering the risk of a leaking boiler.

What are the error codes for a leaking boiler?

Error codes are codes displayed on your boiler that indicate specific problems with your boiler and heating system. This saves you the trouble of having to figure out what is going on with your boiler or even missing the problem already until it is too late and has become a major one!

Most modern boilers with display systems will often showcase error codes for a leaking boiler. Instead of having to sift through your manual, here are the likely error codes associated with leaking boilers for specific brands.

Boiler BrandError Codes
Worcester BoschA1, E9, CE207, HO7
VaillantF.22, F.24, F.13, F.73, S.41, S.53
IdealF1, L1, FD
Baxi117, 118, 125, E78, H.02 – 06

Please note, these are the specific brand models the above likely error codes relate to:

  1. Worcester Bosch: Worcester CDi Class, Worcester CDi Highflow, Worcester CDi Compact, Worcester Greenstar 25i, Worcester Greenstar 30i and all Worcester regular & Worcester system boilers
  2. Vaillant: Vaillant EcoMax Pro, Vaillant EcoTEC Pro, Vaillant EcoTEC Plus
  3. Ideal: Ideal Logic, Ideal Logic Plus, Ideal Mini, Ideal Vogue, Ideal Independent and Ideal Isar
  4. Baxi: all Baxi boiler models included

Hopefully, you now have the knowledge to know how to identify a leaking boiler – and if you ever wish to install a new boiler, Boiler Central is providing the ultimate boiler installation service for you!

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